Process of manufacturing abrasive disks



June 112, 1923. 1,458,322

S. M. BULLOCK ET AL PROCESS OF MANUFACTURING ABRASIVE DISKS Original Filed Sept. 101 i915 \A/FEEEE IUVEQIELHE WW %W' WWW ldatented June 112, 11%23.

entree stares lei-58,322

earner orricn.

AldUEL M. BULLOCK, 03F CHICAGO, AND HARRY S. LI'LQYD, F OAK EFARK, ILLINOIS.

PROCESS @lli MANUFACTURING ABRASIVE DISKS.

Uriginal application filed September 10, 1915, Serial No. cases, Patent No. 1,311,550, dated July 29, 1919. Divided and this application filed July 15, 1919. Serial 1%. 310,967.

To all whom it may concern:

Be it known that we, SAMUEL M. Bun: LOCK and HARRY S. Leora, citizens of the United States, and residents of the city of Chicago and village of Oak Park, respectively, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in a Process of Manuiacturing Abrasive Disks; and we do hereby declare that the following is a fulhclear, and exact description of .thesame, reference being had to the accompanying drawings, and to the numerals of reference marked thereon, which form a part of this specification.

This invention relates to processes for making abrasive wheels, more particularly those used in disk grinders in Whichthe face of the wheel is employed for grinding purposes.

This application'is a division of our Patent No, 1,311,550, dated July 29th, 1919, for Process of forming abrasive disks.

The problem of constructing satisfactory abrasive disks for disk grinders is a difficult one .and various attempts have been made to solve it with only partial success.

Abrasive disks must be made relatively thin to avoid the disk action of centrifugal force and also to avoid the necessity of supporting the axle which carries the disk on each side of the grinding surface.

When glue is employed as a binder the practical limit of thickness is about 3/32" but disks made by our improved method may be considerably thicker. Thus an 18" disk made by one process may be 3/16 thick and a 53" disk 3/8" thick. Usually the thickness of the disks is less than 1%% and more rarely between 1% and 5% of their diameter.

It is impractical to make such disks by baking owing to shrinkage and istortion produced by the heat. especiaily in a disk as thin as above specified.

It" glue is crap eyed as the hinder, the disks must be made excessively thin since as soon as the surface layer of adhesive has worn as and the glue binder is exposed the heat produced by the "friction of the disk against the surface being" ground causes the glue to melt dew. over the surfaces pt the abrasive particles and thereby inhibits their cutting action.

breaking under the By usin I a binder composed of magnesium ehfiride andmagnesium oxide a grinding disk can be made which will retain its cutting action until it has been worn completely away.

Difficulty has, however, been experienced in mounting disks of this character owing to the trouble involved in cementing the disk to its support. We have found that this difliculty may be overcome b using a fabric base for the disk. The fi rous nature of the fabric provides an excellent bonding medium between the abrasive and magnesium mixture on the one hand and also provides a satisfactory support for the glue by which the disk so formed may be secured to the metallic surface of a driving wheel.

It has further been found that if the wetmixture of abrasive, magnesium chloride and magnesite is applied to a dry fabric disk the latter absorbs the magnesium chloride solution from the mixture and seriously interferes with the setting so that instead of a rock-like surface av soft friable surface is obtained.

This dificulty-may be overcome by wetting the fabric before applying the abrasive 'mixture thereto either with plain water or nesium chloride.

It is an object, therefore, of this invention to PIOVldG'flH improved method of associating an abrasive cementitious mixture with a carrier member of fabric or the like.

A further object of the invention is the provision of a method of making abrasive disk with a fabric backing and a layer of abrasive particles bound together and to one side'of the fabric by means of magnesite and magnesium chloride.

her and further important objects of this invention will be apparent from the disclosures in the specification and drawings.

' The invention (in a preferred form} is illustrated in the drawings and hereinafter more fully described.

- On the drawings:

Fire 1 is a front elevation of a disk and driving wheel embodying the "features of the present invention.

Figure 2 is a secticn on the line 2-2 or" Fl "are i.

is shown on the drawings: The fabric disk 2 is first wetted, prefer preferably with a strong solution of magably with a strong solution of magnesium chloride.

Then a mixture of abrasive particles, magnesite and magnesium chloride 15 with magnesite to form a hard substantially insoluble oxychloride.

lhe abrasive mixture may conveniently be made in the following proportions:

75% of a suitable abrasive such as carborundum.

129 96 of magnesium chloride.

129;% of calcined magnesite.

Suflicient water is emplo ed to bring the magnesium chloride into so ution.

For wetting the fabric disk a concentrated solution of magnesium chloride may be used.

In applying the abrasive mixture to the fabric disk any convenient method may be employed such as pressing, tamping, pounding or rolling either by hand or machine.

After the disk has set it may be secured to a driving wheel 3 by applying any suitable adhesive such as sodium silicate or Water glass to the surface of the fabric 2 and, after clamping the disk against the wheel, allowing the same to dry. This will serve to hold the disk rigidly associated with the driving wheel until the disk has become worn necessitating removal thereof. The fabric and remaining portion of abrasive may be torn from the Wheel or the glue or cement may be dissolved by any suitable solvent to perasses mit easy removal of the fabric and the re mainder of the abrasive thereon.

,We are aware that numerous details may be varied through a wide range without departing from the principles of this invention, and we therefore do not purpose limiting the patent otherwise than necessitated by the prior art.

We claim as our invention:

1. The process of forming an abrasive disk comprisin wetting a fabric disk and then applying thereto a mixture of abrasive, calcined magnesite and magnesium chloride solution.

2. The process of forming an abrasive disk comprising wetting a fabric disk with a strong solution of magnesium chloride and then applying thereto a mixture of abrasive calcined magnesite and magnesium chloride solution. 7

3. The process of forming an abrasive disk comprising wetting a fabric disk, applying thereto a mixture of abrasive. calcined magnesite and magnesium chloride solution, allowing the disk to set, and then securing the disk to a rotatable support by means of a soluble adhesive.

"in testimony whereof, We have hereunto subscribed our names in the presence of two subscribing Witnesses.

SAMUEL M. BULLUQK. HARRY S. LLOYD. Witnesses:

EARL M. HARDINE, CHARLES W. Hints, J r. 

